High-density integration of diverse components such as microprocessors, memory, optoelectronics, mixed signal circuits and microelectromechanical systems (MEMS) is a challenging task. One possible solution for high-density integration is three-dimensional stacking, also called three-dimensional integration, of different microelectronic components at the wafer level. The three-dimensional stacking structures offer numerous advantages, including higher density of interconnects, decreased length of interconnects and packaging size or volume reduction.